Many gardeners will be familiar with the appearance of the leaf margins of various shrubs, especially roses, which have had semicircular pieces neatly cut out and removed from some of them. Most, however, will be unaware of the fascinating and industrious insects which are responsible. The disfigurement is the work of leaf-cutter bees, of which two or three species regularly occur in gardens, including those of large cities, within the British Isles.